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Mixed equilibrium/nonequilibrium effects govern surface mobility in polymer glasses
- Publication Year :
- 2024
-
Abstract
- The temperature at which supercooled liquids turn into solid-like glasses ($T_g$) can change at the free surface, affecting the properties of nanostructured glasses and their applications. However, inadequate experimental resolution to determine the $T_g$ gradient and a longstanding debate over the role of nonequilibrium effects have hindered fundamental understanding of this phenomenon. Using spatially resolved $T_g$ measurements and molecular dynamics simulations, we reveal a crossover from equilibrium behavior to a new regime of near-surface nonequilibrium glass physics on cooling. This crossover causes the form of the nonequilibrium $T_g$ gradient to change, highlighting the need to include these physics for rational understanding of the properties of realistic nanostructured glass-forming materials. They also potentially recast the interpretation of decades of experimental data on nanoconfined glasses.<br />Comment: This PDF file includes two documents: The first is the main manuscript, which consists of 13 pages and 4 figures. The second document is the supplementary materials, which contains 25 pages, 8 figures, and 3 tables
- Subjects :
- Condensed Matter - Soft Condensed Matter
Condensed Matter - Materials Science
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.2402.06917
- Document Type :
- Working Paper